CS245062B1 - Method of repairing cement concrete pavements with cement concrete with addition of polymer dispersion - Google Patents

Abstract

The purpose of the invention is to achieve a strong and durable connection between the surface of the old concrete and the layer concreted to it. The stated purpose is achieved by cleaning the treated surface without the need for costly removal of the damaged surface layer, by penetrating it with a diluted aqueous polymer dispersion and by concreting a layer of cement concrete containing an aqueous polymer dispersion and a defoamer, with the aqueous polymer dispersion consisting of a copolymer of styrene acrylates and acrylic acid and added in an amount of 2 to 12 % of the dispersion dry matter per weight of cement, with 360 to 420 kg of cement being dosed per 1 m3 of fresh concrete mix. This method of repair is particularly suitable for repairs of cement concrete roads and airport pavements, and can also be used for repairs of all concrete surfaces and products.

Description

The invention relates to the repair of cementitious pavements with cementitious concrete with the addition of a polymer dispersion on the dispersed penetrated surface, without prior abrasion of the repaired pavement.

Up to now, cement concrete pavement surfaces have been repaired by concreting plain or reinforced slabs separated from existing concrete, or concrete has been admixed with an admixture of polymer dispersion on the underlying concrete, which had to be stripped of the surface layer to a healthy core to ensure good repair concrete. Concreting 150 to 220 millimeters thick, separated plain or reinforced concrete slabs is demanding in terms of performance and material. In addition, operation on such pavements (especially on runways) slips the plates along the separation layer and thereby damages and destroys them. With the existing technology of concrete repair with admixture of polymer dispersion it is necessary to remove the surface layer of old concrete, which is very expensive and time consuming.

The above drawbacks are overcome by the repair method according to the invention. The surface of existing concrete is after mechanical cleaning with steel brushes and water, after drying it is primed with 5- to 10% water dispersion of polymer. Penetration is carried out as long as the dispersion is absorbed into the concrete surface. The excess non-absorbent dispersion is removed from the surface by sweeping. Concreting is carried out after the penetration dispersion has dried in the range of 1 to 48 hours, concrete with admixture of polymer dispersion and antifoam. The connection of the existing concrete with the repair concrete is ensured by connecting the dispersion particles in the repair concrete with the penetration dispersion. The polymer dispersion used does not form a vapor barrier and strengthens the surface of the old concrete sufficiently so that it does not need to be removed. The joint between old and new concrete is strong enough for both materials to act as one slab. The polymer dispersion additive in the repair concrete modifies its modulus of elasticity so that the overconcrete slab can withstand, without damage or tearing, the deformation of the base slab caused by temperature differences between the surface and the bottom of the slab. The addition of an antifoam dispersion to concrete improves the concrete's resistance to the effects of chemical deicing agents 2 to 3 times. The polymer dispersion used also suitably affects the workability of the concrete mix, which ensures perfect processing and bonding of the concrete mix with the underlying concrete.

The above repair method can also be used to repair all other concrete products.

Example

The cement concrete surface is cleaned with a mechanical steel brush and rinsed with water. After drying of the surface, a water dispersion of the polymer having a concentration of 8 to 10% of the dry matter content is penetrated by means of a watering can. Excess non-penetrated dispersion is removed after 10 minutes by sweeping. After the penetration has dried (white color disappears), a layer of 50 to 100 mm thickness of concrete is laid with the following composition:

cement 370 kg water 128 kg silicone antifoam 0.222 kg% polymer dispersion 44.4 kg aggregate 0/8 1000 kg

8/16 720 kg

The concrete mixture is mixed in a conventional concrete mixer, spread by hand and compacted by a vibrating beam. After spreading, the concrete surface is treated by conventional methods used in the construction of cement concrete pavements, preferably by spraying 50% of the polymer dispersion used as an additive in concrete.

Claims (5)

SUBJECT Method for repairing cementitious pavements with cement concrete with the addition of polymer dispersion, without abrasion of repaired concrete, characterized in that after repairing the concrete surface after mechanical treatment, washing with water and drying it is primed with 5 to 10% water dispersion of polymer. After the evaporation of the water from the dispersion, a repair layer of concrete with an admixture of polymer dispersion and antifoam is admixed. 2. Method according to claim 1, characterized in that the fresh concrete mixture for the repair layer of the invention consists of: 360 to 420 kg of cement, 105 to 130 kg of water, 0.1 to 0.3 kg of antifoam, 40 to 55 kg of 50% polymer dispersion, 1700 to 1800 kg of aggregate. 3. The process of claim 1 wherein the aqueous polymer dispersion film comprises groups reacting with alkaline earth metal ions to form insoluble and stable compounds. 4. Process according to claim 1, characterized in that the aqueous dispersion of the synthetic polymer consists of a polymer and / or terpolymer of styrene acrylates and acrylic acid, which is added in an amount of 2 to 12%, preferably 4 to 8% dry matter of the dispersion. . 5. The process of claim 1 wherein the aqueous polymer dispersion comprises from 10% to 10% 50% by weight of styrene, 40 to 75% of alkyl acrylates, for example ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate, 2 to 8% acrylic or methacrylic acid, 2 to 8% methacrylamide and / or methylolmethacrylamide.